Probability revision question

Hi there i`d be thankful for any help anyone out there can give me with this revision question

Q) Anne takes part in a quiz. She has to answer 10 questions. She scores 3 points if she can answer a question correctly by herself. If she cannot answer a question correctly she text messages a friend who may be able to give her the correct answer. If she obtains a correct answer in this fashion she scores 2 points. If not, she loses a point. she estimates that the probability of answering any question correctly by herself is 0.7 and the probability of her friend supplying a correct answer is 0.8

i) what is the probability of Anne answering any given question correctly?

ii) What is the average number of points that Anne will score if she answers 10 questions?

P(X=3) : probab that she answers correctly on her own -> 0.7
P(X=2) : she answers wrong but her friend answers correctly -> 0.3*0.8=0.24
P(X=-1) : she answers wrong and so does her friend -> 0.3*0.2=0.06

The average is : 10(3*P(X=3)+2*P(X=2)-P(X=-1))

And I get something round the answer, but I didn't use any calculator, so do it on your own